Jamie L. Morgan, MD, from the University of Texas Southwestern Medical Center in Dallas, and colleagues conducted a retrospective study at a single institution to compare pregnancy outcomes for those who accepted or declined Tdap at 32 weeks of gestation. Overall, 97% of 7,378 women who were offered Tdap vaccination accepted.

The researchers observed no differences in stillbirth, major malformations, chorioamnionitis, 5-minute Apgar score, or cord blood pH for those who accepted or declined Tdap. Similar results were also seen for neonatal complications, including ventilation requirement, sepsis, intraventricular hemorrhage, and neonatal death. The unvaccinated cohort had significant increases in preterm birth rates at 36 weeks of gestation or less (12 vs. 6 percent; P<0.001); incidence of small for gestational age (15 vs. 10%; P=0.03); and length of neonatal hospitalization (4.7 vs. 3.9 days; P<0.001). Neonatal outcomes did not differ among women who were administered at least two Tdap vaccines in the previous five years and among those who received only a single dose.